October 2012

The Onboard Video system will capture a live feed from each robot and display both feeds on a screen on the off-board device. The video stream should be good enough quality to be able to facilitate both the movement of the device and determine how much to adjust the fine firing control.

Chosen Design - iWebCamera - £3.00

Provides a virtual webcam to your computer by connecting to an iPhone/Ipod touch running iWebcamera. This will provide us with two webcam streams on the raspberry pi, one each from a iphone/ipad on each robot.

The platform of the device will provide a mobile platform to base all the on-board electronics. It should be able to be maneuvered relatively easily as well as being big enough to hold all of the electronics equipment and associated power supplies. The device should be able to be controlled using a number of digital outputs from the Arduino. The power needed for the device should be able to supplied using an on-board battery although this may be a different battery from the one used to power the electronics.

The off-board system refers to the scoring system of the game and the smart phone app that
will allow the user to drive the robot.

Scoring System

When a robot
fires at the other robot and hits a target, they will be awarded a point. The
point value will depend on how easy or hard the target was to hit. When the
sensor is hit, a message will be sent to the main game master to increment the
score of the robot who shot the target. This score will then be displayed on a
screen in the form of a GUI. The figure below demonstrates this.

Offboard System and Robots

Smart Phone App

An app will be
created to allow the user to control the robot. It will have buttons for the
movement of the robot (left, right, forward, backward) and it will also have
buttons to control the firing device (pan left/right, pan up/down, fire).

The firing system is what the robot uses to shoot at the other robot. A robot will have one firing device and multiple targets which will detect the shots fired.

Design

The firing device will be made from a laser diode. A laser diode has a small emission angle meaning that it is very accurate. To detect the laser, a photo transistor will be used. This detects the light and converts it to an electrical signal. The laser diode and photo transistors will be connected to the Arduino, as the Arduino is very good at receiving input from a variety of sensors and also controlling emitters.

This system
should allow the user to move the firing device in small increments after
positioning the robot. An illustration
of the movement can be seen below.
This movement can either be on the x axis or on the y axis, turning the
device horizontally or vertically.

FINE CONTROL OF FIRING DEVICE

Using this
system it will be possible to alter difficulty by limiting range of movement
therefore forcing user to move robot, or speed of movement.

A functional specification has been drawn up in order to clearly define our aims and objectives for this project. This way, we can prioritise time effectively so that the most important objectives can be achieved first, before moving onto secondary ones.

Diagram of whole system

Below can be seen the basic, intermediate and advanced objectives that have been drawn up.

The Raspberry Pi and theArduinoare two very different devices each suited to different activities.

The Arduino is an open-source
electronics prototyping platform. It can receive input from a variety of
sensors and can affect surroundings by controlling lights, motors and other
actuators. It is low power and also has serial communication capability. It is
programmed using the Arduino programming language (based on Wiring) and the
Arduino development environment (based on Processing). The programming language
is very similar to C/C++.

The Raspberry Pi is a single-board
computer that is small in size (85.60 mm × 53.98 mm) and was
developed to aid the teaching of basic computer science in schools. It uses the
Linux operating system. The Pi has a Broadcom system on a chip which includes
an ARM 700 MHz processor, a VideoCore IV GPU, and 256 Mb of RAM. There is not a
built in hard disk but it has an SD card slot.

Arduino (left) and Raspberry Pi (right)

Our embedded systems class requires us to design a 'gadget' using either of these devices. A selection of ideas were put forward: